A polymer having hydroxyl groups at both terminals is able to convert easily the hydroxyl groups into other functional groups by carrying out a suitable reaction on the groups and also, the polymer itself converts into a linear molecule and/or a network molecule by using reactivity of the terminal hydroxyl groups and carrying out a suitable reaction on these hydroxyl groups and, as a result, the polymer becomes a high-molecular compound having excellence in various properties such as strength, heat resistance, weather resistance, durability and so forth.
This polymer having hydroxyl groups at both terminals has, for example, the undermentioned great advantage by displaying a feature such as having the hydroxyl groups at both terminals.
In the case where the polymer is used as various kinds of resin materials such as a polyester resin, polyurethane resin, polycarbonate resin and the like, there is not any unreacted material which may damage material properties, and all polymers are surely assembled in a resin-crosslinked structure.
A polymer which a functional group was introduced into the side chain by copolymerizing a vinyl-based monomer having a functional group such as a hydroxyl group, carboxyl group, an and the like (hereinafter, referred to as "a copolymer of a functional group-containing vinyl-based monomer"); when said polymer was used for a reaction, the terminals become a play part (a free terminal) which is not assembled in the resin (crosslinked) structure, but such a thing does not occur in a polymer having hydroxyl groups at both terminals.
Compared with the copolymer of a functional group-containing vinyl-based monomer, because scattering in the distances among the functional groups is very small, the distances among reacting sites (crosslinking sites) are nearly constant, so that a homogeneous resin (crosslinked) structure is made.
In the case of a copolymer of a functional group-containing vinyl-based monomer, even if the synthesis of a thermoplastic polymer is attempted by making a material of 2.0 in average functional group number and by allowing this to react with a chain-elongating agent having two functionalities, since a polymer having three or more functionalities is statistically included because of a reason originated from the synthetic process, a thermosetting polymer is obtained as the major part, and a thermoplastic polymer can not be synthesized. However, in the case of a polymer having hydroxyl groups at both terminals, and not containing a polymer having three or more functionalities, a thermoplastic polymer, of which chain has been elongated, can be easily synthesized.
The polymer having hydroxyl groups at both terminals, by taking the above-described advantage, is very useful as raw materials for various resins such as a polyester resin, polyurethane resin, polycarbonate resin and the like, and further, as raw materials for coating, tacky and non-tacky adhesive, a sealing compound, urethane foam, a gel court material, thermoplastic elastomer, molding material, resin modifier (a material to afford impact resistance), vibration-controlling material, an elastic wall material, a floor material, fiber-processing material, an UV.EB curing resin, a reactive diluent used for high solid coating, etc. and so forth. In addition, the polymer is useful as various kinds of resin additives and their raw materials.
Preferable examples of the polymer having hydroxyl groups used as raw materials for coating, a tacky and nontacky adhesive, urethane foam, a sealing compound, a gel court material, thermoplastic elastomer, various kinds of molding materials, a resin modifier (a material to afford impact resistance), vibration-controlling material, an elastic wall material, a floor material, fiber-processing material, an UV.EB curing resin, a reactive diluent used for high solid coating, etc. and so forth: those are a copolymer of a vinyl-based monomer having hydroxyl groups on its side chain as well as a polyether, polyester, polybutadiene and polycarbonate having hydroxyl groups at terminals and the like. However, those polymers have the undermentioned problems. At first, since a copolymer of a vinyl-based monomer having hydroxyl groups on its side chain is prepared by a random type radical polymerization reaction between a vinyl-based monomer having the hydroxyl group and a vinyl-based monomer having no hydroxyl group, by-product formation of a copolymer having no hydroxyl group is difficult to suppress and, in order to avoid this formation, it is necessary to increase the hydroxyl group content in the copolymer and also, there was found scattering in the number of hydroxyl groups contained in one molecule. Because of this, in a case where a reaction was carried out between the copolymer of a vinyl-based monomer having hydroxyl groups on its side chain and a polyfunctional compound capable of reacting with the hydroxyl groups, a polymer showing sufficient stretching (processing performance for bending is excellent) and strongness is not obtained by reasons of remaining unreacted copolymer and large scattering in distances among reaction sites, and by that a play chain part which does not directly participate in the structure of a crosslinked polymer obtained after reaction is formed and a hydroxyl group not participating in the reaction remains.
Next, a polyether, polyester, polybutadiene and the like having hydroxyl groups at terminals, because they have the hydroxyl groups at terminals, have a little defect that a copolymer of a vinyl-based monomer having hydroxyl groups on its side chain has. However, in the case of polyethers because of the ether bond on the main chain, in the case of polyesters because of the ester bond on the main chain, and in the case of polybutadiens because of the unsaturated double bond on the main chain, these polymers have defects such as badness in weather resistance, water resistance and heat resistance.
As described above, at present, in a polymer having hydroxyl groups, which is used as raw materials for coating, a tacky and non-tacky adhesive, urethane foam, a sealing compound, gel court material, thermoplastic elastomer, various kinds of molding materials, a resin modifier (a material to afford impact resistance), vibration-controlling material, an elastic wall material, a floor material, fiber-processing material, an UV.EB curing resin, a reactive diluent used for high solid coating, etc. and so forth; there is not found any member satisfactory for all demands and capabilities such as strongness, stretching (processing performance for bending), weather resistance, water resistance and so forth.
Although it is considered that a problem of this sort may be solved by a vinyl-based polymer having hydroxyl groups at both terminals, as mentioned below, the real situation is that any process for producing industrially a polymer having hydroxyl groups at both terminals from a wide range of vinyl-based monomers involving polar vinyl-based monomers such as acrylic acid, acrylate, methacrylic acid, methacrylate and the like has not been established.
An example of a process for producing a vinyl-based polymer having hydroxyl groups at terminals is a process such as introducing one hydroxyl group into one terminal of the polymer by using, for example, 2-mercaptoethanol and the like as a chain-transfer agent and introducing another one (as an average) hydroxyl group into a polymer molecule by copolymerizing with 2-hydroxyethyl methacrylate and the like.
However, in this process, al though two hydroxyl groups per one molecule of a polymer are introduced as average, only one of the two hydroxyl groups is introduced into one terminal of the polymer and another hydroxyl group is introduced into the middle of a main chain, but not into the terminal. Furthermore, since another hydroxyl group is introduced by a copolymerization reaction, the to total number of hydroxyl groups per one molecule of the polymer is in a scatter distribution such as being from one to three or more, and a wide distribution is seen in the distances among hydroxyl groups. Accordingly, an obtained polymer can not almost display any merit which the polymer having hydroxyl groups at both terminals has. Furthermore, by adding a mercaptan compound, there were problems that the polymerization reaction became extremely slow, the polymerization degree did not raise, and the smell of residual mercaptan remained.
Other examples of a process for producing a vinyl-based polymer having hydroxyl groups at both terminals are, as shown in the undermentioned (i) to (iii), processes of carrying out radical polymerization reactions of vinyl-based monomers in the presence of various kinds of initiators and chain-transfer agents.
(i) A process for producing a polymer having hydroxyl groups at both terminals by polymerizing styrene or butadiene by using an initiator having the hydroxyl group. Refer to Journal of Polymer Science, Part A1, Volume 9, p. 2029 (1971). PA1 (ii) A process for producing a polymer having hydroxyl groups at both terminals, comprising a thermal polymerization reaction or a photopolymerization reaction carried out by using a dithiocarbamate or thiuram disulfide having the hydroxyl group as an initiator, or comprising a polymerization reaction carried out by using the dithiocarbamate or thiuram disulfide as a chain transfer agent and using hydrogen peroxide as an initiator. Refer to Japanese Official Patent Provisional Publication, showa 61-271306. PA1 (iii) A process for producing a polymer having hydroxyl groups at both terminals, comprising a polymerization reaction carried out by using a disulfide or trisulfide having hydroxyl groups at both terminals as a chain transfer agent. Refer to Japanese Official Patent Provisional Publication, showa 54-47782. PA1 1 A process which comprises using two kinds or more of polyols as the polyol component (1) containing the polymer having hydroxyl groups at both terminals obtained from the production method of this invention and carrying out a reaction of the polyols with a compound having two or more of a functional group capable of reacting with a hydroxyl group per one molecule. PA1 2 A process which comprises carrying out a reaction of the polymer having hydroxyl groups at both terminals obtained from the production method of this invention with a polymer having only one hydroxyl group per one molecule and a compound having two or more of a functional group capable of reacting with the hydroxyl group per one molecule. PA1 3 A process which comprises carrying out a reaction of the polymer having hydroxyl groups at both terminals obtained from the production method of this invention with a compound having two or more of a functional group capable of reacting with the hydroxyl group per one molecule. PA1 4 A process which comprises using the polymer having hydroxyl groups at both terminals obtained from the production method of this invention as an initiator and obtaining an ABA type block polymer by carrying out a ring-opening polymerization reaction of one kind or two or more kinds of a cyclic ether such as ethylene oxide, propylene oxide, tetrahydrofuran and the like.
However, the aforementioned, conventional processes for producing a polymer having hydroxyl groups at both terminals (i) to (iii) have respective defects, as mentioned below, and it is not easy to synthesize a polymer having hydroxyl groups at both terminals surely, with a cheap price, simply and industrially, from many kinds of vinyl-based monomers.
At first, in Process (i), there was a problem that usable vinyl-based monomers were limited to butadienes and styrenes, and polar vinyl-based monomers such as acrylates and methacrylates could not be used.
In the aforementioned process (ii), there was a problem that the thiuram disulfide having a functional group such as a hydroxyl group is unstable and, thereby, its treating was difficult and also, a produced polymer was colored in yellow.
Finally, in the aforementioned process (iii), there is a problem that, because attention to the ratio of a chain-transfer agent to an initiator is not paid, in a case where the chain-transfer agent is not sufficiently in excess compared with the amount of an initiator, a flake of the initiator is introduced into the terminals of a polymer and a polymer having the hydroxyl group at only one terminal is formed as a by-product and, therefore, a polymer having the terminal hydroxyl groups in a low number is formed.
As described above, at the present time there has not been established any process for producing industrially a polymer having hydroxyl groups at both terminals from a wide field of vinyl-based monomers including polar vinyl-based monomers such as acrylic acid, acrylate, methacrylic acid, methacrylate and the like.
Under these circumstances, it is an object of the present invention to provide a process for obtaining a polymer having hydroxyl groups at both terminals easily, with a cheap price and good efficiency, from a wide field of vinyl-based monomers including polar vinyl-based monomers such as acrylic acid, acrylate, methacrylic acid, methacrylate and the like, a composition containing this polymer and showing superiority in strongness, weather resistance, water resistance and so forth, and its use, and a polymer derived from the composition and its use.